Loom for weaving



March 14, 1967 E. PFARRWALLER LOOM FOR WEAVING 2 Sheets-Sheet 1 Original Filed Jan. 13, 1964 Jn wen/0r: fRW/N FFARRWALLER March 14, 1967 E. PFARRWALLER LOOM FOR WEAVING 2 Sheets-Sheet 2 Original Filed Jan. 13, 1964 uwv.

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flrrok/vfy United States Patent 3,308,854 LOOM FOR WEAVING Erwin Pfarrwaller, Winterthur, Switzerland, assignor to Sulzer Brothers Limited, Winterthur, Switzerland, a corporation oft Switzerland Continuation of application Ser. No. 337,268, Jan. 13,

1964. This application Oct. 19, 1965, Ser. No. 511,265 Claims priority, application Switzerland, Jan. 22, 1963, 609/63 Claims. (Cl. 139-99) This application is a continuation of my copending application, Ser. No. 337,268, filed Jan. 13, 1964, now abandoned.

The present invention relates to a weaving machine including a positively driven take-up roller which takes up the cloth by friction, a warp beam driven through an adjustable transmission whose input drive is derived from the rotation of the take-up roller and a control device for controlling the transmission ratio of the variable transmission to compensate for variations in the diameter of the roll of warp on the warp beam.

Take-up rollers which take up the cloth by friction are occasionally referred to as sand beams since they have rough surfaces for frictional engagement with the cloth.

The invention takes advantage of the fact that the cloth take-up roller of a loom is always driven at a speed corresponding to the proposed weft density, the drive to the take-up roller being through a variable transmission such as a change-gear transmission if required. By derivingthe input drive for the adjustable transmission driving the warp beam from the rotation of the take-up roller the warp delivery speed appropriate for the cloth take-up is adjusted automatically for all weft densities. Moreover, the warp delivery control device which compensates for variations in the diameter of the roll of warp can be arranged to operate always in the best range. Further, by deriving the input drive for the adjustable transmission driving the warp beam directly from the rotation of the take-up roller, the sense of direction of rotation of the Warp beam always coincides with the sense of rotation of the take-up roller so as to maintain the proper tension in the cloth.

It is important to maintain the predetermined tension in the warp and cloth at all times in order to obtain a fabric without flaws in the weave. Thus when a rupture of a weft thread has been detected, usually after a number of subsequent unrupted weft threads has been run, the

machine has to be rolled back by hand to correct the de-- fect. However, in the machines of the prior art, when the take-up roller is rolled back there is no corresponding rolling back of the warp beam. Hence, the tension in the warp and cloth is lost. In fact, in a known machine, the take-up roller is driven by a drive shaft through a shiftable coupling which is adapted to reverse the normal direction of rotation of the take-up roller for the return of the weft thread when it is operated by a weft stop motion. However, the warp beam of the machine is driven by the shaft through a variable speed transmission in only the normal direction of rotation. Consequently, when the take-up roller is rolled back by hand, the warp beam is not coincidently rolled back and the required tension in the cloth is lost. Thus, upon redriving the machine a number of weft threads will be picked up before the required tension returns to the cloth. Because of this, an unattractive flaw will appear in the final cloth and such becomes extremely critical in fine fabrics such as rayon.

The invention allows the warp beam to be rolled back by hand with the take-up roller so as to maintain the required tension for weaving and to prevent the appearance of flaws in the cloth.

The control device for controlling the variable transice mission may include a war-p tensioning beam or may include a feeler arranged to engage the roll of warp on the warp beam. Alternatively, the warp tensioning beam may be used as a fine control for warp delivery, of use mainly for evening out irregularities in the roll of warp, this fine control being superimposed upon a coarse control provided by a warp roll diameter feeler with the result that the fine control does not have to compensate warp delivery for the progressive decrease in the warp roll diameter. Thus the fine control provided by the warp tensioning beam need be used only to compensate for irregularities in the winding of the warp on to the warp beam and for the extra length of warp yarn required to embrace the weft yarn, this amount being a factor which varies with the fabric. The latter quantity, the so-called in weave, is equal to:

the length of the warp minus the length of the cloth the length of the cloth Consequently, the warp tensioning beam remains approximately in its central position during weaving and does no more than deflect slightly either side of this central position. Accordingly, the control device does not have to allow for movement of the tensioning beam progressively from one end of its travel to the other during weaving as the diameter of the warp roll decreases. It is advantageous for the tensioning beam to remain approximately in its central position throughout weaving since a selected tension originally determined for the upper and lower shed positions remains unchanged. Consequently, the looping angle of the warp threads in the upper and lower shed positions about the inserted weft threads remains substantially constant so that the quality of the cloth remains substantially constant. The approximately constant central position of the tensioning beam is useful even though the cloth may be rocked during weaving because of different tensioning of the warp threads in the upper shed and lower shed positions.

The invention may be carried into practice in various ways and a loom embodying the invention will now be described by way of example with reference to the accompanying drawings in which:

FIGURES 1a and lb represent a part-sectional elevation of a loom according to the invention, only parts which are of importance to the invention being shown.

FIGURE 2 is an end view of a portion, of the loom shown in FIGURE 1.

FIGURE 3 is an end view of a detail pertaining to the mechanism shown in FIGURE 2.

Referring more particularly to the drawing wherein like parts are designated by like numerals in all figures, the loom stands on a base 20 having a pit 10 and comprises two side uprights, only one of which can be seen in FIG- URE 1 and is designated by numeral 1. The two uprights are interconnected by one or more transverse beams. The uprights and the beams form the loom frame. A warp 2 runs from a warp beam 3 at the rear of the loom over a tensioning roller 6, which can pivot about the axle 4 of a bearing beam 5 and which is loaded by a spring 95, and through a number of healds 7 to a temple 8. To the rear of the temple 8, at 9, is the location yarns introduced into a shed 11 are beaten up by a reed, not shown. After passing the temple 8 the cloth 12 travels over a rough-surface take-up roller (sand beam) 13 and a presser roller 14 on to a cloth beam 15 at the front of the loom.

The loom has a drive means at the front driven through shaft 16 which is driven at the same speed as the main shaft, not shown, and on which is mounted a worm 17 engaging a worm wheel 18. A gear 21 is secured to the shaft 19, FIG. 2, of the worm wheel 18 by means of a where the weft.

. 48b to a shaft 25 which constitutes the drive means for the let-off and the take-up motions. Disposed on the shaft 25 is a gear 27 engaging with a pinion 28 mounted on one end of a shaft 29 having secured to its other end a bevel gear 31 engaging with another bevel gear 32. The shaft 33 of the latter drives the warp beam 3 in a manner which will be described in greater detail below.

Also mounted on the shaft 25 is a gear 34 which engages with a gear 35 on a hollow shaft 36 which is' pushed onto the shaft 19 and on which a gear 37 is disposed. The gear 37 engages with a gear 38 which engages with a gear 39 driving the take-up roller (sand beam) 13. The presser roller 14 is freely rotatable.

Secured to the hollow shaft 36 isa sprocket wheel 41 which drives the cloth beam through a chain 42 and a sprocket wheel 43 which is coupled to the cloth beam through a slipping coupling 40. The shaft 22 of the gear pair 23, 24 is mounted in a slot 44 in a triangular supporting plate 45 which is pivotally mounted on the shaft 25 inside the upright 1 and prevented from rotating by means of a screw 47 which extends through another slot 46 in the supporting plate 45. To change the change gears 21, 23, 24, 26, the screws 47, 48, 48a, 48b are first slackened, and then the gears are changed, then the supporting plate 45 is pivoted around the shaft 25 far enough for the new gears to engage with one another. The screw 47 is then tightened with the parts in this position.

The shaft 33 drivesfvia a universal joint 49, a shaft 51 and via another universal joint 52, a shaft 53 at the warp beam end of the loom. On the shaft 53 is a V-pulley formed by two pulley discs 54, 55 of which the disc 54 is secured to the shaft 53 and the disc 55, while rotating with the shaft 53, can move axially thereon. The pulley disc 55 is loaded by a spring 50 which tends to move it to the right in FIGURE la. The left end of the spring 50 bears against a shaped member 112 which is screwed to the shaft 53 and which has a beveled surface 111.

The pulley discs 54, 55 drive a V-belt 56 which drives another V-pulley formed by two pulley discs 57, 58 which are mounted on a shaft 61, the pulley disc 57 being fixed thereto whereas the pulley disc 58, although non-rotatable thereon, can move axially on the shaft 61. 'When the disc 58 moves to the right in FIGURE 1a, the effective diameter of the pulley pair 57, 58 is reduced and the spring 50 can push the element 55 to the right whereby the effective diameter of the pulley pair 54, 55 is increased. The stepup provided by the variable-speed transmission 54-58, which forms a warp delivery control device or warp-governing device, is therefore also increased.

A shaped element 113 which has a beveled surface 114 and a peripheral flange 115 is rotatable and axially displaceably mounted on the left end of the shaft 53. The flange 115 engages in grooves 116 in pull rods 117 screwed into the pulley disc 55. A hand wheel 101 normally on the shaft 61 can be fitted to the shaped element 113 to rotate it until the beveled surfaces 114, 111 register with one another. Upon further rotation of the shaped element 113, the disc 55 is pulled to the left by the rods 117 so that the V-belt 56 ceases to be tensioned. Consequently, the driving elements, which will be described in greater detail hereinafter, of the warp beam 3 and the warp beam itself can be turned by hand for initial adjustment.

Extending into the path of the movable disc 58 is a double-armed lever 64, 65 which is pivo-table around a pin 63 rigidly mounted on the loom frame, the arm 64 of the lever carrying a roller 62 engaging with a collar with the roller 62.

The arm 65 of the lever 64, ,65 is connected by a pivot 66 to a link 68 formed with an arcuate slot 67, which contains a slide block 69. The distance between the center line 68a of the slot and the pivot 66 of the link 68 is greater on the radius b; consequently, when the link 68 is pivoted clockwise around the pivot 66, the pivot and also the rest of the link 68 are moved to the left in'FlG- URE 1 because of the presence of the slide block 69 in the slot 67. When the link 68 is pivoted counterclockwise, the pivot 66 and the rest of thelink 68 are moved to the right.

The slide block 69 is mounted on an approximately trapezoidal plate 72 which is pivotable around a pin 71 rigidly mounted on the loom frame and to which is connected, at a point 73, one end of a tension spring 74 tending to turn the plate 72 counterclockwise around the pin 71. The second end of the spring 74 is made fast on the loom frame. The plate 72 has at its top end a roller 75 engaging with a cam surface 76 of a substantially triangular cam 77. The cam can pivot around a stationary axis 78 and is loaded by a tension spring 81 which is connected to the cam at 79 and which tends to turn the cam 77 and a feeler 82 connected thereto clockwise around the axis 78 and thus to maintain the feeler in engagement with the roll of warp on the warp beam 3.

The link 68 is connected by a pivot pin 83 to a rod 84 which is shown broken in the drawing to improve visibility. The rod 84 is provided with a slot 85. A pin 88 extends into the slot and is mounted on a lever 89 which is pivoted on the stationary axle 4 of the beam 5. The lever 89 is rotatably coupled with a double-armed lever 92, 93. The tensioning beam 6 is fitted to the arm 92, while teeth 94 on the arm 93 receive one end of a tension spring which tends to turn the lever 92, 93, clockwise around the axle 4 and thus to tension the warp 2. The movement of the end of the lever 89 to which the pin 88 is mounted and thereby the movement of the pin in the slot 85 is limited by the two heads of two adjustable screws 86 and 87.

The characteristics of the spring 95 are such, and the lever 92, 93 and the teeth 94 are so devised, that the torque applied to the warp tensioning beam 6 by the spring 95 is thesame whatever the position of the lever 92, 93. The warp tension is therefore the same for all positions of the tensioning beam 6, with slight momentary changes due to the mass'inertia of the tensioning-beam system. Iftoo' little or too much warp is paid off from the warp beam, the tensioning beam 6 makes a slight downward or upward movement, respectively, from its substantially constant central position. With the tensioning beam 6 in its new position the Warp tension is the same as previously.

A Worm 96 mating with a worm wheel 97 is disposed on the shaft 61 carrying the V-pulley pair 57, 58. Fitted to the worm wheel shaft is a gear 98 which meshes with a driving gear 99 connected to the warp beam 3. The warp beam can be rotated by hand by the hand wheel 101, so that the warp 2 can be tensioned initially, for instance, after introduction of the warp beam into the loom.

The system operates as follows: The take-up roller 13, the cloth beam 15 and the warp beam 3 are driven continuously by the shaft 16 during weaving. If too little warp yarn is let off as compared with the take-up of cloth, the tensioning beam 6 is gradually lowered in FIGURE 1 so that the lever 89 is pivoted counterclockwise and the nod 84 is moved upward in FIGURE 1a after any lost motion in the slot 85 has first been taken up. The link 68 therefore pivots clockwise around the pivot 66 and is aaoassi moved to the left so that the lever 64, 65 is turned counterclockwise around the pivot 63. The roller 62 moves to the right. The element 58 follows the roller 62 due to the previously described action of the spring 50, whereby the active radius of the V-pulley 57, 58 is decreased and that of the V-pulley 54, 55 is increased and the rotational speed of the shaft 6land therefore of the warp beam 3is increased. More warp yarn is therefore paid off from the warp beam per unit of time so as to correspond to the take-up.

If the warp yarn pay-01f is excessive, the movements of the elements just described occur in opposite directions; the tensioning beam 6 temporarily rises and the transmission ratio provided by the system 5458and therefore the speed of the warp beam-decreases, so that less warp yarn is paid off per unit of time.

The lost motion usually operative on both sides between the pin 88 and the screws 86, 87 is to ensure that slight movements of the tensioning beam 6 which occur after each pick because of the beating-up action of the reed at 9 are not transmitted via the rod 84 to the V-pulley 58, only major movements of the beam 6 due to irregularities in the warp winding being so transmitted.

The warp beam speed control produced in dependence upon the position of the tensioning beam 6 by axial shifting of the pulley disc 58, and the elements required for this purpose, form a fine control for the warp beam drive. To vary the extent of speed variation of the warp beam 3 produced by the fine controli.e., to vary the sensitivity of the controlthe pin 88 can be introduced into one of a number of additional holes 89a or 8% in the lever 89.

As the warp roll diameter decreases, the feeler 82 and the cam 77 pivot farther and farther in clockwise direction. The cam surface 76 therefore moves slowly past the roller 75 so that the trapezoidal plate 72 together with the slide block 69 can be gradually turned counterclockwise around the pivot 71 by the spring 74. The link 68 and its pivot 66 are therefore also turned counterclockwise around the pivot 63, so that the mean value of the speed of the shaft 61, and also the extreme values of such speed which oscillate about this mean value and which are produced by the fine control system 6, 84 are progressively increased. The elements 82, 77, 72, 69 therefore form a coarse control for the warp beam speed, such control operating in dependence upon the instantaneous diameter of the roll of warp.

Since the drive for the warp beam control device 54-58 is effected after the cloth take-up change gears 21, 23, 24, 26i.e., at the shaft 25 and therefore by the rotation of the take-up roller 13-the control action of the coarse sys tern 82, 77, 72, 69 and of the fine system 6, 84, 68-whose effects are superimposed one upon another and act on the V-pulley system 54-58-can be used over a very wide control range adequate for almost all kinds of weave found in practice. The V-pulley discs 54, 55, 57, 58 need not have a very large diameter. For instance, in one practical construction the shaft 16 runs at the loom speed n=200 revolutions per minute (=number of picks). Different change gears 21, 23, 24, 26 can be used to vary the transmission ratio from the shaft 19 to the shaft 25 between 1:8 and 3:1, to correspond to weft densities of from 91 to 3.6 yarns/cm. The speed of the universal shaft 51 varies correspondingly between n/42=4.75 rpm. and 3n/5=120 r.p.m. The correctly controlled warp pay-off is adjusted automatically within this wide range of drive speeds which is suitable for almost all conventional weft densities. The V-belt drive 54-58 can be replaced with any other form of steplessly variable transmission, such as a friction-wheel transmission.

Various modifications are possible; for example, the slide block 69 can be immovably mounted on the loom frame and the elements 72, 74, 77, 81, 82 can be omitted. In this case there is no coarse control by a feeler in dependence upon the instantaneous diameter of the roll of warp, and the regulation of warp pay-01f in accordance with the decreasing roll diameter must be provided for by the control which is associated with the tensioning beam 6 and which is operative via the elements 89, 84, 68, 65, 64. In this case the tensioning beam 6 must move farther and farther down in FIGURE 1 as the diameter of the roll of warp decreases in order that warp beam speed may be increased in the required manner by the linkage 89, 84, 68. In this case the slide block will not remain in contact with the central region of the slot 67 throng-bout; instead, the link 68 must be so placed when the lap diameter is large-i.e., at the startthat the slot 67 is relatively far up and the smaller distance [1 is operative. As the warp roll diameter decreases during weaving, the descending tensioning beam 6 turns the link 68 so that the larger distance a becomes operative and the transmission ratio provided by the V-belt drive 54-58 increases. The different distances b and a must provide all the compensation for the effect of lap diameter on warp pay-off. Consequently, if the slide block 69 is stationary, the control provided by the tensioning beam 6 alone cannot be as sensitive as in the embodiment comprising a controlled slide block as illustrated in FIG. 1a.

The take-up roller 13 must always be driven positively. The drive is usually continuous but may be intermittent. A particularly useful feature in cases where the cloth take-up and warp pay-off are driven continuously is that, since the warp pay-off control system 54-58 derives its drive from the take-up roller 13, severe overshoot of the warp pay-off control is avoided, i.e., the warp beam does not hunt between running too fast and running too slowly. Consequently, if the drive is continuous, the warp yarns are not subjected to such great changes in stress as they would be with an intermittent drive and are therefore less severely treated, so that there is less risk of warp breakages. Also, the finished fabric is more uniform, since a predetermined length of warp yarn is paid off at each pick, unlike other systems where no warp yarn is paid off during a number of picks and a length of warp thread must be paid off subsequently by a single large motion of the warp beam.

What is claimed is:

1. A loom for weaving, comprising a drive means positioned at the loom front,

a cloth take-up roller operatively connected directly to said drive means in an inseparable, inflexible manner to be driven thereby, said cloth take-up roller including means for frictionally engaging a cloth,

a variable speed transmission positioned at the loom rear operatively connected directly to said drive means to be directly dn'ven thereby at an input speed corresponding in rigid relation to the speed of rotation of said take-up roller, and in a direction corresponding to the direction of rotation of said take-up roller,

a warp beam operatively connected solely to said variable-speed transmission to be driven thereby,

means operatively connected to said variable-speed transmission for varying the speed ratio of said transmission whereby the speed of said Warp beam 1 is varied with respect to the speed of said take-up roller.

2. A loom as set forth in claim 1 wherein said means includes a warp tensioning roller mounted on a pivotal means, the position of said warp tensioning roller being responsive to the length of the warp between said warp beam and said take-up roller.

3. A loom as set forth in claim 1 wherein said means includes a feeler engaging and being responsive to the roll of warp on said warp beam.

4. A loom for weaving comprising a cloth take-up roller including means for frictionally engaging a cloth,

drive means for driving said take-up roller,

a variable-speed transmission operatively connected to said drive means to be directly driven thereby at an input speed corresponding in rigid relation to the speed of rotation of said take-up roller,

a Warp beam operatively connected solely to said variresponding to the speed of rotation of said take-up able-speed transmission to be driven thereby in autov roller, matici: responseto thedinput speed of said variablea warp tbeam, said \tiaiatble-spieed tragsm ssi on belnig spee transmission, an opera ive y connec e sm Warp earn ror so e y means operatively connected to said transmission for 5 driving said warp beam in automatic response to the varying the speed ratio of said transmission and speed of said drivim member, and including a tensioning roller and a feeler, said ten- 7 means responsive to ihe diameter of the roll of Warp sioning roller being operatively connected to a pivoton said Warp beam and being peratively connected ally mounted movable link having an arcuate slot to said vanable-speed transmission for varying the therein of varying distance from the pivot of said 10 speed ratio thereof. link, said feeler being operatively connected to a V slide block'slidably mounted in the slot of said link 7 References Clted by the Examiner whereby said tension roller constitutes a fine control UN T S S PATENTS and said feeler constitutes a coarse control for the v Warp beam speed which are superimposed. g ii et 5. A loom for weaving comprising a cloth take-up roller including means for frictionally 2820485 1/1958 Sales 139*99 engaging acloth 2,914,092 11/1959 Clentimack 139-l08 drive means positioned at the loom front for driving 2920659 1/1960 Pfarrwauer 139*110 said take-up roller and including change gears com- FOREIGN PATENTS prising exchangeable gears for changing the speed of rotation of said take-up roller and a driving 11,582 1884 Great U P member operatively connected between said change 8611345 2/1961 Great Bmalngears and said take-up roller, a variable-speed transmission positioned at the loom MERVIN STEIN Primary Examiner rear operatively connected to said driving member S. JAUDON Assistant Examinen to be directly driven thereby at an input speed cora 

1. A LOOM FOR WEAVING, COMPRISING A DRIVE MEANS POSITIONED AT THE LOOM FRONT, A CLOTH TAKE-UP ROLLER OPERATIVE CONNECTED DIRECTLY TO SAID DRIVE MEANS IN AN INSEPARABLE, INFLEXIBLE MANNER TO BE DRIVEN THEREBY, SAID CLOTH TAKE-UP ROLLER INCLUDING MEANS FOR FRICTIONALLY ENGAGING A CLOTH, A VARIABLE SPEED TRANSMISSION POSITIONED AT THE LOOM REAR OPERATIVELY CONNECTED DIRECTLY TO SAID DRIVE MEANS TO BE DIRECTLY DRIVEN THEREBY AT AN INPUT SPEED CORRESPONDING IN RIGID RELATION TO THE SPEED OF ROTATION OF SAID TAKE-UP ROLLER, AND IN A DIRECTION CORRESPONDING TO THE DIRECTION OF ROTATION OF SAID TAKE-UP ROLLER, A WARP BEAM OPERATIVELY CONNECTED SOLELY TO SAID VARIABLE-SPEED TRANSMISSION TO BE DRIVEN THEREBY, MEANS OPERATIVELY CONNECTED TO SAID VARIABLE-SPEED TRANSMISSION FOR VARYING THE SPEED RATIO OF SAID TRANSMISSION WHEREBY THE SPEED OF SAID WARP BEAM IS VARIED WITH RESPECT TO THE SPEED OF SAID TAKE-UP ROLLER. 